Yaik Wah Lim

Internal Shading for Efficient Tropical Daylighting in Malaysian Contemporary High-Rise Open Plan Office

In tropical climate, there is actually abundant quantity of daylight but yet to be utilised. The excessively high and unpredictable external illuminance could cause non-uniform indoor illuminance distribution and visual discomfort. In order to improve daylighting quality in contemporary high-rise open plan offices, proper design of internal shading should be investigated. A base model was derived from previous case studies for simulation using Radiance. Various venetian blinds, vertical blinds and light shelves were configured for the experiment. Daylight factor (DF) was evaluated for quantitative performance; work plane illuminance (WPI) distribution and vertical plane luminance ratio were investigated for qualitative performance. The findings demonstrated that generally blinds were not a good potential for daylight utilisation but good in reducing luminance contrast. Light shelves improved performances in DF and WPI distribution but increased the luminance contrast. Hence, integrations of light shelves and partial venetian blind (45° closed) were proposed as the effective designs for all orientations. The highest improvements of 31.8% in WPI distribution and 66.7% in luminance ratio were achieved for south and east orientations, respectively. This paper demonstrates that with proper internal shading design, effective daylighting depth can be significantly improved from typically used 2.5u2009H rule of thumb to 3.6u2009H.

The effects of direct sunlight on light shelf performance under tropical sky

As daylight is dynamic, there is no one common solution for all scenarios. Understanding of sky conditions is the fundamental to effective daylighting. It is more critical in tropical climate where the sky is predominantly intermediate with inconsistent presence of direct sunlight (DSL). Thereby, daylighting performances of several light shelf configurations were experimented with physical scaled model under actual tropical sky conditions. External illuminance and indoor work plane illuminance (WPI) levels were measured concurrently in a reference model and a test model for comparisons. Daylight ratio or daylight factor and WPI uniformity ratio were computed for analysis. From the results, different optimum cases were identified for various sky conditions. Light shelves performed the best under intermediate sky with DSL from low angle. The highest improvement in WPI at deep room area and WPI uniformity were 24.87% and 364.96%, respectively. The performances of light shelves under overcast sky were better than light shelf under intermediate sky without DSL. This paper concluded that designing light shelf by responding to changeable sky conditions and DSL is more crucial than considering the façade orientations. Dynamic light shelf was proposed to configure the optimum cases for each tropical sky conditions.

Empirical validation of Radiance-IES daylight simulation for furnished and unfurnished rooms under a tropical sky

AbstractNowadays, many researchers – especially engineers and architects – apply daylighting simulation tools during the building design process to investigate daylighting performance for a range of purposes. However, International Commission on Illumination (CIE, from the French name of the organisation, Commission Internationale de l’Eclairage) sky models are considered for many such simulation tools. The characteristics of tropical sky are different from those of CIE skies, hence the usage and validity of these tools could be unreliable for research involving tropical regions. The aim of this study is to validate the Radiance program in the Integrated Environmental Solution – Virtual Environment (IES-VE) software by measuring daylight in furnished and unfurnished rooms under Malaysian tropical sky. Daylighting measurement and simulation were carried out over eight days in unfurnished and furnished rooms under both intermediate and overcast skies. The case room was drawn by ModelIT and the related furni...

BIM-based sustainable building design process and decision-making

Sustainability is a major concern in the building industry due to the climate change and depletion of energy sources. Nevertheless, the current process of sustainable building design depends on various disjointed analyses to meet the different required sustainability performances. Building information modeling (BIM) allows for complex buildings being digitally modeled with accurate geometry and information for sustainable design process and decision-making during the early design stages. Therefore, the aim of this study is to integrate BIM with sustainable building design decision-making by considering the tropical climatic contexts in Malaysia. A BIM-based decision-making framework (DMF) was developed based on review on related literature and green building certifications as well as BIM tools evaluation. The proposed DMF supports design decision-making at multiple BIM Level of Development (LOD). Based on the framework, Revit template was developed to extract BIM data for decision-making. The research output deals with the challenges of decision-making in the early building design process by allowing for specific sustainability performance analyses.

Optimization of green building design to achieve green building index (GBI) using genetic algorithm (GA)

Designing a feasible green building that complies with national green building assessment is one of the main problems faced by architects. The existing Building Information Modelling (BIM) software, is used by architects to assist them to design a green building. Green building is a concept where the building is environmentally friendly to the surrounding, does not use too much electricity and have low Overall Thermal Transfer Value (OTTV). Architects having some tough time to design green building because OTTV of the building majorly affected by wall and window material used. Hence in this study, single objective Genetic Algorithm (GA) is proposed to optimize green building designed by BIM. A decision support system using GA optimization is proposed to optimize green building designed using BIM. The goal is to find an optimum material combination that produces nearly optimum OTTV. The initial result shows that GA manages to find optimum materials combination with a reduced 16% OTTV.